What Are Solar Panels Made Of?
One common question homeowners and business owners want to ask is, what are solar panels made of? This question is mostly asked by individuals seeking to have an in-depth knowledge of the ‘physics’ behind photovoltaic (PV) panels. There is no straightforward answer to the question. This is because PV panels are made of various types.
This article looks into crystalline-silicon and thin-film PV panels, which are the most common types.
Crystalline Silicon Solar Panels
Crystalline silicon (c-Si) PV panels usually come to mind at the mentioning of a solar panel. It is because they are the most common panel product on the market. They are made of rectangular grids of small squares, blue or black in color.
The small squares are silicon cells forming a circuit in a series. A series production capacity depends on the number of cells that are interconnected. A series with more interconnected cells produces more electricity than a series with fewer cells.
Most crystalline panels have between 60 and 72 cells per series. Panels with fewer cells are also available and are commonly used in the off-grid market.
Series of cells in a solar panel is usually connected with a busbar. Busbar ribbons are excellent in creating higher voltages and are made of copper or aluminum. The number of busbars in a solar panel contributes to the panel’s efficiency. A solar panel with more busbars has higher efficiency, and hence, can produce more power.
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It is worth noting that crystalline-silicon PV panels are also categorized into two groups: monocrystalline and polycrystalline. The main difference between the two types is their manufacturing method. Monocrystalline solar panels use a single crystal that is cut into distinctive patterns, giving their recognizable appearance.
On the other hand, polycrystalline solar panels are made by pouring molten silicon into a cast. This manufacturing method creates boundaries where the formation breaks, giving the solar panel a grainy appearance.
Polycrystalline solar panels usually have lower efficiency rates than monocrystalline panels due to their manufacturing method. Hence, the polycrystalline panel is cheaper than its monocrystalline counterpart.
Thin-Film Solar Panels
Photovoltaic panels of this variety are more used in large-scale installations. Thin-film panels are made by depositing a thin semiconductor on plastic, glass, or metal foil substrates. As the name suggests, thin-film solar panels are thin and flexible.
Their flexibility and lightweight are great features that make them an excellent choice for installations on curved roofs or automobiles. Though thin-film solar cells have lower efficiency levels than silicon panels, the amount of material they contain is quite lower in creating a cell.
The Outer Structure of Panels
Regardless of the manufacturing method, solar panels generally consist of a protective back sheet on the backside and a glass layer on the front. Most solar PV panels have back sheets made of polymer that is usually white. However, modern modules now look into other colors for aesthetic reasons.
Finally, to complete the full manufacturing process, the panel periphery is made of an aluminum frame. The frame adds strength to the panel and protects the edges of the glass. The frame also helps in mounting the system to the roof or ground.